Assessing the overlooked interaction between bacterial communities and antibiotics at the sea surface microlayer of coastal environments (IBCASSMic)

• Applicant: Adenike Adenaya, Ph.D.
• Subject Area: Microbial Ecology and Applied Microbiology ; Analytical Chemistry
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 553816530

Antibiotics and other pharmaceutical compounds are contaminants of emerging concern due to their persistence and bioaccumulation in aquatic life. Global antibiotic consumption increased by 65% from 2000 to 2015, with an expected increase of up to 200% by 2030. This poses a threat to marine and coastal waters' biodiversity and ecological integrity. Many studies have investigated the presence of antibiotics and their influence on bacterial communities in freshwater and coastal settings. Nevertheless, there is a gap in knowledge concerning the interaction and dynamics between antibiotics and bacterial communities in the sea surface microlayer (SML) of coastal environments. The SML is a challenging and intricate environment that exposes microbial communities to anthropogenic pollutants like heavy metals, polyaromatic hydrocarbons, and microplastics. Introducing antibiotics in the environment adds extra stressors to the bacterial communities. This research study aims to examine the impact of antibiotics on the structure, function, diversity, and dynamics of bacterial communities in the SML of coastal environments. The study will specifically focus on the Baltic Sea (Germany) and the Tropical Atlantic Ocean in Cape Verde. The study has two main objectives. Firstly, to analyze the concentrations of target antibiotics and other pharmaceutical contaminants in the SML and the corresponding underlying water and investigate the hydrodynamic conditions that could aid their accumulation in the SML of coastal environments. Sec-ondly, to assess the responses of bacterial communities to exposure scenarios and evaluate the potential impacts on the structure, function, and diversity of bacterial communities within the SML and underlying water of the two coastal environments. The study will be conducted at different locations with varying levels of human influence to comprehend the 'natural' levels and human-induced effects, as well as in waters with significantly different biogeochemical starting conditions. These locations include the Baltic Sea (Germany) and the tropical waters surrounding the Cape Verde archipelago, specifically on São Vicente Island (Cape Verde). Mesocosm experiments will be used to study the hydrodynamic conditions, such as temperature, that could facilitate the accumulation of target compounds in the SML. Additionally, laboratory experiments will be employed to investigate the effects of antibiotics on bacterial community composition and functions in the SML and underlying water of coastal environments. The research project will utilize analytical chemistry and cellular and molecular methods to achieve its objectives.

• DFG Programme: WBP Position